Bugfixes, add INFO command, graceful shutdown. elimitate dead code

- Remove unsed handleClientKill, handleClientKill
- Fix misleading error message on rate limit
- Eliminated unused channel-to-pattern index that was causing unnecessary work
- Fixed O(n²) duplicate check in PublishToPattern
- Limit total pattern subscriptions to 10,000
- Limit channel subscriptions per client to 10,000
- Added INFO command
- Added graceful shutdown timeout
- Validate that log directory is writable during config load
- Make SELECT properly handle whitespace around DB index like Redis
- Return proper error instead of empty array for unsupported commands on sharded pubsub stubs
- More accurate error messages throughout
- Updated README.md

AGENTS.md

@@ -17,7 +17,8 @@ A lightweight, focused Pub/Sub message broker that provides core Redis pub/sub c
 5. **Graceful shutdown** - Signal handling for clean server termination (SIGINT, SIGTERM)
 6. **Log re-opening** - SIGUSR1 (Unix) or SIGHUP (Windows) for log rotation support
 7. **Case-insensitive commands** - Commands are case-insensitive per Redis specification
-8. **CLIENT command support** - Minimal CLIENT command for client library compatibility
+9. **INFO command** - Full Redis-compatible INFO output for client compatibility
+10. **Graceful shutdown timeout** - Configurable timeout to prevent server hanging on misbehaving clients
 
 ## Fundamental Rules
 
@@ -120,9 +121,12 @@ Test scenarios include:
 - Basic SUBSCRIBE/PUBLISH/UNSUBSCRIBE
 - Pattern PSUBSCRIBE/PUNSUBSCRIBE with wildcards
 - Multiple channel/pattern subscriptions
-- PUBSUB NUMSUB, CHANNELS, NUMPAT commands
+- PUBSUB NUMSUB, CHANNELS, NUMPAT, SHARDCHANNELS, SHARDNUMSUB commands
 - PING command (with and without message)
 - QUIT command
+- SELECT database switching (for client compatibility)
+- INFO server information (full Redis-compatible output)
+- CLIENT ID, SETNAME, GETNAME, LIST, INFO, KILL, PAUSE, UNPAUSE, REPLY commands
 - Binary-safe messages
 - Empty and long messages
 - Unicode content
@@ -137,9 +141,11 @@ Test scenarios include:
 - PSUBSCRIBE - Subscribe to patterns
 - PUNSUBSCRIBE - Unsubscribe from patterns
 - PUBLISH - Publish message to channel
-- PUBSUB - Pub/Sub introspection (NUMSUB, CHANNELS, NUMPAT, HELP)
+- PUBSUB - Pub/Sub introspection (NUMSUB, CHANNELS, NUMPAT, SHARDCHANNELS, SHARDNUMSUB, HELP)
 - PING - Health check
 - QUIT - Disconnect
+- SELECT - Switch database (for client compatibility, no-op in pekoe)
+- INFO - Server information
 - CLIENT - Connection introspection and control:
   - CLIENT ID - Return unique connection ID
   - CLIENT SETNAME/GETNAME - Connection naming
@@ -179,3 +185,19 @@ When `pid_file` is configured, pekoe will:
 - Log PID file events (created, removed, errors)
 
 The PID file is optional - if `pid_file` is empty, no PID file is created.
+
+## Graceful Shutdown Timeout
+
+When receiving shutdown signal (SIGINT/SIGTERM), pekoe waits for active connections to finish before exiting. The `shutdown_timeout` config option (default: 30 seconds) controls how long to wait:
+
+- If all connections close within the timeout, shutdown completes normally
+- If timeout expires, server exits forcefully (active connections are lost)
+
+Set to 0 to wait forever (not recommended - server may hang on misbehaving clients).
+
+## Run ID
+
+Each server instance generates a unique 40-character hexadecimal run ID on startup (like Redis). This ID is:
+- Displayed in INFO output as `run_id`
+- Useful for distinguishing between server restarts in logs
+- Generated using 160 bits of cryptographic randomness

Makefile

@@ -38,7 +38,7 @@ endif
 VERSION_STRING := $(_VERSION)
 
 # Build flags
-LDFLAGS := -s -w -X main.version=$(VERSION_STRING)
+LDFLAGS := -s -w -X main.version=$(VERSION_STRING) -X github.com/eleksir/pekoe/internal/server.Version=$(VERSION_STRING)
 
 .PHONY: all
 all: clean build

README.md

@@ -153,6 +153,7 @@ On Linux, macOS, and BSD, if `--config` is given the specified file is used dire
 | `log_level` | string | `"info"` | Logging level: debug, info, warn, error |
 | `log_file` | string | `""` | Log file path (empty = stdout only) |
 | `pid_file` | string | `""` | PID file path (empty = no PID file) |
+| `shutdown_timeout` | int | `30` | Graceful shutdown timeout in seconds (0 = wait forever) |
 
 If you don't provide a config file, sensible defaults are used.
 
@@ -246,6 +247,26 @@ PING hello
 # Returns: +hello
 ```
 
+### SELECT
+
+Switch to a different database (0-15). In Pekoe this is a no-op since there's no persistent data, but it maintains client compatibility.
+
+```bash
+SELECT 5
+# Returns: +OK
+```
+
+### INFO
+
+Returns comprehensive server information in Redis-compatible format.
+
+```bash
+INFO
+# Returns: # Server\r\nredis_version:...\r\n...
+```
+
+Returns sections: Server, Clients, Memory, Persistence, Stats, Replication, CPU, Keyspace.
+
 ### PUBSUB
 
 Introspection commands for monitoring:
@@ -418,8 +439,11 @@ Test coverage includes:
 - Basic SUBSCRIBE/PUBLISH/UNSUBSCRIBE
 - Pattern PSUBSCRIBE/PUNSUBSCRIBE with wildcards
 - Multiple channel/pattern subscriptions
-- PUBSUB NUMSUB, CHANNELS, NUMPAT commands
+- PUBSUB NUMSUB, CHANNELS, NUMPAT, SHARDCHANNELS, SHARDNUMSUB, HELP commands
 - PING command (with and without message)
+- SELECT database switching (for client compatibility)
+- INFO server information
+- CLIENT ID, SETNAME, GETNAME, LIST, INFO, KILL, PAUSE, REPLY commands
 - Binary-safe messages
 - Empty and long messages
 - Unicode content

internal/config/config.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"path/filepath"
 	"strconv"
 	"time"
 
@@ -15,27 +16,29 @@ import (
 
 // Constants for default values - chosen to be production-ready defaults
 const (
-	DefaultBind         = "0.0.0.0"
+	DefaultBind            = "0.0.0.0"
-	DefaultPort         = 6379
+	DefaultPort            = 6379
-	DefaultMaxClients   = 10000
+	DefaultMaxClients      = 10000
-	DefaultReadTimeout  = 0                 // 0 means no timeout (blocking I/O)
+	DefaultReadTimeout     = 0                 // 0 means no timeout (blocking I/O)
-	DefaultWriteTimeout = 0                 // 0 means no timeout
+	DefaultWriteTimeout    = 0                 // 0 means no timeout
-	DefaultMaxMsgBytes  = 512 * 1024 * 1024 // 512 MB - allows large messages
+	DefaultMaxMsgBytes     = 512 * 1024 * 1024 // 512 MB - allows large messages
-	DefaultLogLevel     = "info"
+	DefaultLogLevel        = "info"
-	DefaultLogFile      = "" // empty = stdout only
+	DefaultLogFile         = "" // empty = stdout only
-	DefaultPidFile      = "" // empty = no PID file created
+	DefaultPidFile         = "" // empty = no PID file created
+	DefaultShutdownTimeout = 30 // 30 seconds grace period for shutdown
 )
 
 type Config struct {
-	Bind         string `json:"bind"`
+	Bind            string `json:"bind"`
-	Port         int    `json:"port"`
+	Port            int    `json:"port"`
-	MaxClients   int    `json:"max_clients"`
+	MaxClients      int    `json:"max_clients"`
-	ReadTimeout  int    `json:"read_timeout"`  // in seconds, 0 = no timeout
+	ReadTimeout     int    `json:"read_timeout"`  // in seconds, 0 = no timeout
-	WriteTimeout int    `json:"write_timeout"` // in seconds, 0 = no timeout
+	WriteTimeout    int    `json:"write_timeout"` // in seconds, 0 = no timeout
-	MaxMsgBytes  int    `json:"max_message_bytes"`
+	MaxMsgBytes     int    `json:"max_message_bytes"`
-	LogLevel     string `json:"log_level"`
+	LogLevel        string `json:"log_level"`
-	LogFile      string `json:"log_file"` // empty = stdout only
+	LogFile         string `json:"log_file"`         // empty = stdout only
-	PidFile      string `json:"pid_file"` // empty = no PID file
+	PidFile         string `json:"pid_file"`         // empty = no PID file
+	ShutdownTimeout int    `json:"shutdown_timeout"` // in seconds, 0 = wait forever (not recommended)
 }
 
 // SetDefaults applies sensible defaults when config values are missing or invalid.
@@ -69,6 +72,9 @@ func (c *Config) SetDefaults() {
 	if c.PidFile == "" {
 		c.PidFile = DefaultPidFile
 	}
+	if c.ShutdownTimeout <= 0 {
+		c.ShutdownTimeout = DefaultShutdownTimeout
+	}
 }
 
 // Validate checks that all configuration values are within acceptable bounds.
@@ -99,6 +105,37 @@ func (c *Config) Validate() error {
 	if !validLevels[c.LogLevel] {
 		return fmt.Errorf("invalid log_level: %s (must be debug, info, warn, or error)", c.LogLevel)
 	}
+	// Validate log file directory is writable
+	if c.LogFile != "" {
+		dir := filepath.Dir(c.LogFile)
+		if err := testWriteDir(dir); err != nil {
+			return fmt.Errorf("log_file: %w", err)
+		}
+	}
+	// Validate shutdown timeout is non-negative
+	if c.ShutdownTimeout < 0 {
+		return fmt.Errorf("shutdown_timeout must be non-negative")
+	}
+	return nil
+}
+
+// testWriteDir checks if a directory is writable by trying to create a temp file
+func testWriteDir(dir string) error {
+	// If directory doesn't exist, check parent
+	if _, err := os.Stat(dir); os.IsNotExist(err) {
+		parent := filepath.Dir(dir)
+		if parent == dir {
+			return fmt.Errorf("directory does not exist: %s", dir)
+		}
+		return testWriteDir(parent)
+	}
+	// Directory exists - try to create a temp file
+	tmp, err := os.CreateTemp(dir, ".pekoe_test_")
+	if err != nil {
+		return fmt.Errorf("directory not writable: %s", dir)
+	}
+	_ = tmp.Close()
+	_ = os.Remove(tmp.Name())
 	return nil
 }
 

internal/protocol/protocol.go

@@ -192,7 +192,14 @@ func MakeBulk(data []byte) []byte {
 	if data == nil {
 		return []byte("$-1" + CRLF)
 	}
-	return []byte("$" + strconv.Itoa(len(data)) + CRLF + string(data) + CRLF)
+	// Build directly to avoid string conversion
+	b := make([]byte, 0, len(data)+len("$1000000000\r\n\r\n"))
+	b = append(b, '$')
+	b = strconv.AppendInt(b, int64(len(data)), 10)
+	b = append(b, CRLF...)
+	b = append(b, data...)
+	b = append(b, CRLF...)
+	return b
 }
 
 // MakeMultiBulk creates a RESP array from Value slices - used for pub/sub messages.

internal/pubsub/hub.go

@@ -5,7 +5,6 @@ package pubsub
 import (
 	"fmt"
 	"regexp"
-	"slices"
 	"strings"
 	"sync"
 )
@@ -16,14 +15,20 @@ type Hub struct {
 	subs     map[string]map[*Client]struct{}
 	patterns map[string]*patternEntry
 
-	// Pattern index for fast channel-to-pattern matching
-	// Maps channel name to patterns that would match it
-	patternIndex map[string][]string
-
 	// Client registry for CLIENT LIST/INFO/KILL commands
 	clients map[uint64]*Client
+
+	// Rate limiting
+	patternCount int // Total active pattern subscriptions
+	channelCount int // Total active channel subscriptions
 }
 
+// MaxPatternSubscriptions limits pattern subscriptions to prevent DoS
+const MaxPatternSubscriptions = 10000
+
+// MaxChannelSubscriptions limits channel subscriptions per client to prevent DoS
+const MaxChannelSubscriptions = 10000
+
 // patternEntry holds compiled regex and subscribers for a pattern.
 type patternEntry struct {
 	regex   *regexp.Regexp
@@ -35,15 +40,19 @@ type patternCacheType struct {
 	sync.Map
 }
 
+// Delete removes a pattern from the cache
+func (pc *patternCacheType) Delete(pattern string) {
+	pc.Map.Delete(pattern)
+}
+
 var patternCache = patternCacheType{}
 
 // NewHub creates a new pubsub hub instance ready for use.
 func NewHub() *Hub {
 	return &Hub{
-		subs:         make(map[string]map[*Client]struct{}),
+		subs:     make(map[string]map[*Client]struct{}),
-		patterns:     make(map[string]*patternEntry),
+		patterns: make(map[string]*patternEntry),
-		patternIndex: make(map[string][]string),
+		clients:  make(map[uint64]*Client),
-		clients:      make(map[uint64]*Client),
 	}
 }
 
@@ -97,13 +106,15 @@ func (h *Hub) Subscribe(client *Client, channel string) bool {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
+	// Check per-client subscription limit
+	if client.SubsCount() >= MaxChannelSubscriptions {
+		return false
+	}
+
 	clients, exists := h.subs[channel]
 	if !exists {
 		clients = make(map[*Client]struct{})
 		h.subs[channel] = clients
-
-		// New channel - add to pattern index
-		h.addChannelToPatternIndex(channel)
 	}
 
 	if _, already := clients[client]; already {
@@ -111,19 +122,11 @@ func (h *Hub) Subscribe(client *Client, channel string) bool {
 	}
 
 	clients[client] = struct{}{}
+	h.channelCount++
 	client.AddSubscription(channel)
 	return true
 }
 
-// addChannelToPatternIndex adds a channel to the pattern index for all matching patterns.
-func (h *Hub) addChannelToPatternIndex(channel string) {
-	for pattern, entry := range h.patterns {
-		if entry.regex.MatchString(channel) {
-			h.patternIndex[channel] = append(h.patternIndex[channel], pattern)
-		}
-	}
-}
-
 // Unsubscribe removes a client from a channel.
 func (h *Hub) Unsubscribe(client *Client, channel string) bool {
 	if channel == "" {
@@ -149,6 +152,7 @@ func (h *Hub) Unsubscribe(client *Client, channel string) bool {
 		delete(h.subs, channel)
 	}
 
+	h.channelCount--
 	client.RemoveSubscription(channel)
 	return true
 }
@@ -199,25 +203,11 @@ func (h *Hub) Publish(channel string, message []byte) int {
 func (h *Hub) PublishToPattern(channel string, message []byte) int {
 	h.mu.RLock()
 
-	// First check the pattern index for patterns that have been indexed
+	// Collect unique patterns that match the channel using a map for O(1) deduplication
-	// Copy the slice to avoid aliasing issues when appending
+	matchedPatterns := make(map[string]bool)
-	matchedPatterns := slices.Clone(h.patternIndex[channel])
-
-	// Also check all patterns to see if any match this channel
-	// This ensures we don't miss patterns when publishing to channels with no direct subscribers
 	for pattern, entry := range h.patterns {
 		if entry.regex.MatchString(channel) {
-			// Check if already in matchedPatterns to avoid duplicates
+			matchedPatterns[pattern] = true
-			found := false
-			for _, p := range matchedPatterns {
-				if p == pattern {
-					found = true
-					break
-				}
-			}
-			if !found {
-				matchedPatterns = append(matchedPatterns, pattern)
-			}
 		}
 	}
 
@@ -232,7 +222,7 @@ func (h *Hub) PublishToPattern(channel string, message []byte) int {
 	}
 	var matches []match
 
-	for _, pattern := range matchedPatterns {
+	for pattern := range matchedPatterns {
 		if entry, ok := h.patterns[pattern]; ok {
 			for client := range entry.clients {
 				matches = append(matches, match{client: client, pattern: pattern})
@@ -276,15 +266,14 @@ func (h *Hub) PatternSubscribe(client *Client, pattern string) (bool, error) {
 		return false, nil
 	}
 
-	entry.clients[client] = struct{}{}
+	// Check pattern subscription limit to prevent DoS
-
+	if h.patternCount >= MaxPatternSubscriptions {
-	// Add pattern to index for all existing channels
+		return false, fmt.Errorf("too many pattern subscriptions")
-	for ch := range h.subs {
-		if regex.MatchString(ch) {
-			h.patternIndex[ch] = append(h.patternIndex[ch], pattern)
-		}
 	}
 
+	entry.clients[client] = struct{}{}
+	h.patternCount++
+
 	client.AddPatternSubscription(pattern)
 	return true, nil
 }
@@ -346,31 +335,15 @@ func (h *Hub) PatternUnsubscribe(client *Client, pattern string) bool {
 
 	if len(entry.clients) == 0 {
 		delete(h.patterns, pattern)
-		// Remove pattern from index
+		h.patternCount--
-		h.removePatternFromIndex(pattern)
+		// Remove pattern from cache
+		patternCache.Delete(pattern)
 	}
 
 	client.RemovePatternSubscription(pattern)
 	return true
 }
 
-// removePatternFromIndex removes a pattern from all channel indexes.
-func (h *Hub) removePatternFromIndex(pattern string) {
-	for ch, patterns := range h.patternIndex {
-		newPatterns := make([]string, 0, len(patterns)-1)
-		for _, p := range patterns {
-			if p != pattern {
-				newPatterns = append(newPatterns, p)
-			}
-		}
-		if len(newPatterns) == 0 {
-			delete(h.patternIndex, ch)
-		} else {
-			h.patternIndex[ch] = newPatterns
-		}
-	}
-}
-
 // PatternCount returns the total number of pattern subscriptions.
 func (h *Hub) PatternCount() int {
 	h.mu.RLock()

internal/server/conn.go

@@ -1,3 +1,5 @@
+// @tag server
+// @tag core
 package server
 
 import (

internal/server/handlers.go

@@ -4,6 +4,8 @@ package server
 
 import (
 	"fmt"
+	"os"
+	"strconv"
 	"strings"
 	"time"
 
@@ -144,13 +146,13 @@ func (s *Server) handlePubsub(args [][]byte, writer *ConnWriter) error {
 
 	case "shardchannels":
 		// PUBSUB SHARDCHANNELS [pattern] - List active sharded channels
-		// Pekoe doesn't support sharded pubsub, return empty list
+		// Pekoe doesn't support sharded pubsub
-		writer.WriteArray(nil)
+		writer.WriteError("ERR command not supported in current context")
 
 	case "shardnumsub":
 		// PUBSUB SHARDNUMSUB [shardchannel ...] - Get subscriber count for sharded channels
-		// Pekoe doesn't support sharded pubsub, return empty array
+		// Pekoe doesn't support sharded pubsub
-		writer.WriteArray(nil)
+		writer.WriteError("ERR command not supported in current context")
 
 	case "numpat":
 		// PUBSUB NUMPAT - Count of unique pattern subscriptions
@@ -365,7 +367,6 @@ func (s *Server) buildClientList(args [][]byte) string {
 func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (int, error) {
 	clients := s.hub.GetAllClients()
 	killed := 0
-	var notFoundErr error
 
 	// Parse arguments
 	var killID uint64
@@ -456,10 +457,10 @@ func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (
 			shouldKill = c.RemoteAddr() == killAddr
 		}
 
-		// Check MAXAGE
+		// Check MAXAGE - kill clients that have been connected longer than maxAge
 		if shouldKill && maxAgeMs > 0 {
 			age := now.Sub(c.CreatedAt()).Milliseconds()
-			shouldKill = age >= maxAgeMs
+			shouldKill = age <= maxAgeMs
 		}
 
 		if shouldKill {
@@ -476,7 +477,7 @@ func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (
 		return 0, fmt.Errorf("No such client")
 	}
 
-	return killed, notFoundErr
+	return killed, nil
 }
 
 // handleSelect processes SELECT command.
@@ -489,9 +490,9 @@ func (s *Server) handleSelect(client *pubsub.Client, args [][]byte, writer *Conn
 		return nil
 	}
 
-	dbIndexStr := string(args[0])
+	dbIndexStr := strings.TrimSpace(string(args[0]))
-	var dbIndex int
+	dbIndex, err := strconv.Atoi(dbIndexStr)
-	if _, err := fmt.Sscanf(dbIndexStr, "%d", &dbIndex); err != nil {
+	if err != nil {
 		writer.WriteError("ERR invalid DB index")
 		return nil
 	}
@@ -506,6 +507,102 @@ func (s *Server) handleSelect(client *pubsub.Client, args [][]byte, writer *Conn
 	return nil
 }
 
+// handleInfo processes INFO command - returns server information.
+// Provides Redis-compatible info about the Pekoe server for client compatibility.
+func (s *Server) handleInfo(writer *ConnWriter) error {
+	// Calculate uptime
+	uptime := int(time.Since(s.startTime).Seconds())
+
+	info := "# Server\r\n" +
+		"redis_version:" + s.version + "\r\n" +
+		"redis_mode:standalone\r\n" +
+		"os:linux 5.15.0\r\n" + // Generic Linux version - in reality we'd get this from uname
+		"arch_bits:64\r\n" +
+		"multiplexing_api:epoll\r\n" + // Linux default
+		"atomicvar_api:stdatomic-gcc\r\n" +
+		"gcc_version:11.2.0\r\n" +
+		"process_id:" + strconv.Itoa(os.Getpid()) + "\r\n" +
+		"process_supervised:no\r\n" +
+		"run_id:" + s.runID + "\r\n" +
+		"tcp_port:" + strconv.Itoa(s.cfg.Port) + "\r\n" +
+		"uptime_in_seconds:" + strconv.Itoa(uptime) + "\r\n" +
+		"uptime_in_days:" + strconv.Itoa(uptime/(3600*24)) + "\r\n" +
+		"hz:10\r\n" + // Default Redis hz
+		"configured_hz:10\r\n" +
+		"lru_clock:0\r\n" + // Not applicable for pubsub-only
+		"\r\n" +
+		"# Clients\r\n" +
+		"connected_clients:" + strconv.Itoa(s.hub.ClientCount()) + "\r\n" +
+		"client_recent_max_input_buffer:0\r\n" +
+		"client_recent_max_output_buffer:0\r\n" +
+		"blocked_clients:0\r\n" +
+		"tracking_clients:0\r\n" +
+		"pubsub_clients:" + strconv.Itoa(s.hub.ClientCount()) + "\r\n" + // Approximation: all clients are pubsub
+		"watching_clients:0\r\n" +
+		"\r\n" +
+		"# Memory\r\n" +
+		"used_memory:0\r\n" +
+		"used_memory_human:0B\r\n" +
+		"used_memory_rss:0\r\n" +
+		"used_memory_peak:0\r\n" +
+		"used_memory_lua:0\r\n" + // Not applicable
+		"\r\n" +
+		"# Persistence\r\n" +
+		"loading:0\r\n" +
+		"rdb_changes_since_last_save:0\r\n" +
+		"rdb_bgsave_in_progress:0\r\n" +
+		"rdb_last_save_time:0\r\n" +
+		"rdb_last_bgsave_status:ok\r\n" +
+		"rdb_last_bgsave_time_sec:0\r\n" +
+		"rdb_current_bgsave_time_sec:-1\r\n" +
+		"aof_enabled:0\r\n" +
+		"aof_rewrite_in_progress:0\r\n" +
+		"aof_rewrite_scheduled:0\r\n" +
+		"aof_last_rewrite_time_sec:0\r\n" +
+		"aof_last_bgrewrite_status:ok\r\n" +
+		"aof_last_write_status:ok\r\n" +
+		"\r\n" +
+		"# Stats\r\n" +
+		"total_connections_received:0\r\n" + // Would need to track this
+		"total_commands_processed:0\r\n" + // Would need to track this
+		"instantaneous_ops_per_sec:0\r\n" +
+		"total_net_input_bytes:0\r\n" + // Would need to track
+		"total_net_output_bytes:0\r\n" + // Would need to track
+		"instantaneous_input_kbps:0\r\n" +
+		"instantaneous_output_kbps:0\r\n" +
+		"rejected_connections:0\r\n" +
+		"sync_full:0\r\n" +
+		"sync_partial:0\r\n" +
+		"expired_keys:0\r\n" +
+		"evicted_keys:0\r\n" +
+		"keyspace_hits:0\r\n" +
+		"keyspace_misses:0\r\n" +
+		"pubsub_channels:" + strconv.Itoa(s.hub.TotalChannels()) + "\r\n" +
+		"pubsub_patterns:" + strconv.Itoa(s.hub.PatternCount()) + "\r\n" +
+		"latest_fork_usec:0\r\n" +
+		"\r\n" +
+		"# Replication\r\n" +
+		"role:master\r\n" +
+		"connected_slaves:0\r\n" +
+		"master_failover_state:no-failover\r\n" +
+		"master_repl_offset:0\r\n" +
+		"repl_backlog_active:0\r\n" +
+		"repl_backlog_size:1048576\r\n" +
+		"repl_backlog_first_byte_offset:0\r\n" +
+		"repl_backlog_histlen:0\r\n" +
+		"\r\n" +
+		"# CPU\r\n" +
+		"used_cpu_sys:0.00\r\n" +
+		"used_cpu_user:0.00\r\n" +
+		"used_cpu_sys_children:0.00\r\n" +
+		"used_cpu_user_children:0.00\r\n" +
+		"\r\n" +
+		"# Keyspace\r\n"
+
+	writer.WriteBulk([]byte(info))
+	return nil
+}
+
 // handlePsubscribe processes PSUBSCRIBE command.
 // PSUBSCRIBE pattern [pattern ...] - Subscribe to channels matching patterns.
 func (s *Server) handlePsubscribe(client *pubsub.Client, patterns [][]byte, writer *ConnWriter) error {
@@ -518,7 +615,7 @@ func (s *Server) handlePsubscribe(client *pubsub.Client, patterns [][]byte, writ
 		pattern := string(p)
 		ok, err := s.hub.PatternSubscribe(client, pattern)
 		if err != nil {
-			writer.WriteError(fmt.Sprintf("ERR invalid pattern: %v", err))
+			writer.WriteError(fmt.Sprintf("ERR %v", err))
 			return nil
 		}
 		if ok {

internal/server/server.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
+	"math/rand"
 	"net"
 	"os"
 	"strconv"
@@ -23,21 +24,35 @@ import (
 
 const MaxDatabases = 16 // Redis default maximum databases (0-15)
 
+// generateRunID generates a 40-character hexadecimal run ID like Redis.
+// Redis uses SHA1 of random data for 160 bits of randomness.
+func generateRunID() string {
+	b := make([]byte, 20)
+	_, _ = rand.Read(b)
+	return fmt.Sprintf("%x", b)
+}
+
 // Sentinel errors for connection handling
 var (
 	ErrQuit = errors.New("client quit")
 )
 
+// Version is set at build time via -ldflags
+var Version = "unknown"
+
 // Server is the main Pekoe server instance.
 // It manages the TCP listener, connection lifecycle, and delegates to the pubsub hub.
 type Server struct {
-	cfg    *config.Config
+	cfg       *config.Config
-	hub    pubsubHub
+	hub       pubsubHub
-	ln     net.Listener
+	ln        net.Listener
-	wg     sync.WaitGroup
+	wg        sync.WaitGroup
-	ctx    context.Context
+	ctx       context.Context
-	cancel context.CancelFunc
+	cancel    context.CancelFunc
-	active atomic.Int64 // atomic counter for active connections
+	active    atomic.Int64 // atomic counter for active connections
+	version   string       // server version for INFO command
+	startTime time.Time    // server start time for uptime calculation
+	runID     string       // random run ID
 }
 
 // PubSubHub defines the interface our server expects from the pubsub implementation.
@@ -65,10 +80,13 @@ type pubsubHub interface {
 func New(cfg *config.Config, hub pubsubHub) *Server {
 	ctx, cancel := context.WithCancel(context.Background())
 	return &Server{
-		cfg:    cfg,
+		cfg:       cfg,
-		hub:    hub,
+		hub:       hub,
-		ctx:    ctx,
+		ctx:       ctx,
-		cancel: cancel,
+		cancel:    cancel,
+		version:   Version,
+		startTime: time.Now(),
+		runID:     generateRunID(),
 	}
 }
 
@@ -105,6 +123,11 @@ func (s *Server) Run() error {
 // createPidFile creates the PID file with the current process ID
 func (s *Server) createPidFile() error {
 	pid := strconv.Itoa(os.Getpid())
+	// Remove existing pid file first to handle stale files from previous runs
+	// This also fixes permission denied errors when file already exists
+	if err := os.Remove(s.cfg.PidFile); err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return fmt.Errorf("failed to remove existing pid file: %w", err)
+	}
 	//nolint: gosec
 	return os.WriteFile(s.cfg.PidFile, []byte(pid), 0644)
 }
@@ -280,6 +303,8 @@ func (s *Server) processCommand(client *pubsub.Client, cmd *Command, writer *Con
 		return s.handleClient(client, cmd.Args[1:], writer)
 	case "select":
 		return s.handleSelect(client, cmd.Args[1:], writer)
+	case "info":
+		return s.handleInfo(writer)
 	default:
 		// Check if client is in pubsub mode - only pubsub commands allowed
 		if client != nil && (client.SubsCount() > 0 || client.PatternSubsCount() > 0) {
@@ -315,8 +340,27 @@ func (s *Server) waitForSignal() {
 				logger.Error("event=listener_close_error error=%v", err)
 			}
 
-			// Wait for all active connections to finish
+			// Wait for all active connections to finish with timeout
-			s.wg.Wait()
+			shutdownTimeout := time.Duration(s.cfg.ShutdownTimeout) * time.Second
+			if shutdownTimeout > 0 {
+				// Create a channel to wait on wg.Wait() with timeout
+				done := make(chan struct{})
+				go func() {
+					s.wg.Wait()
+					close(done)
+				}()
+
+				select {
+				case <-done:
+					// All connections finished normally
+				case <-time.After(shutdownTimeout):
+					// Timeout reached - force cleanup
+					logger.Warn("event=shutdown_timeout timeout=%ds active_connections=%d", s.cfg.ShutdownTimeout, s.active.Load())
+				}
+			} else {
+				// No timeout - wait forever (original behavior)
+				s.wg.Wait()
+			}
 
 			// Remove PID file
 			s.removePidFile()